Over the last five years Rockstar's titles have seen a subtle shift in tone. The publisher has always been known for creating fantastic experiences, but in the past, their titles provided an intoxicating mix of mature-themed content and boisterous fun. Their best games – most notably the groundbreaking Grand Theft Auto series – allowed players free-run in brilliantly constructed worlds. They contained a great deal of violence, sure, but all of it was wrapped up in satirical humour and a cartoon-like veneer, which conspired the take the edge off.

This all changed with Grand Theft Auto IV in 2008, which saw Rockstar's open world environment presented as a living, breathing city which was better and more believably constructed than ever before. The game also boasted one of the best stories in any game that year, following Niko Bellic, ex-soldier from Eastern Europe, as he tried to make an honest living in his new chosen homeland, the United States. Bellic was a classic noir character; his quest for the American Dream was a starting point, but gradually, as he ran afoul of shady characters and desperate situations, he was forced to turn to the talents he'd learned in war to survive. As a result, hell opened up beneath his feet.

Bellic, it turned out, was one of the first of a series of fully-fleshed characters to star in a Rockstar title. Over the next few years, the publisher's GTA DLC and Red Dead Redemption releases presented players with a host of damaged characters; all of whom had violent pasts, all of whom were surrounded by antagonists and danger and all of whom were trying to make good in the worst possible circumstances. Rockstar's protagonists are no longer ciphers, like the silent Claude Speed in GTA III. They are complete, well rounded individuals that the player comes to care about.

This strong emphasis on character is more front and center than ever before in Rockstar's upcoming game, L.A. Noire. Set in 1947, the game follows the fortunes of one Cole Phelps, a soldier back from the war turned policeman on the means streets of Los Angeles. The post-war period setting instantly brings to mind classic noir entertainment such as Chinatown, The Big Sleep and L.A. Confidential; here, perhaps more so than in any Rockstar game before it, players find themselves walking in a world of shadows and intrigue. Phelps is a man set against the rules of his time; he's an honest cop trying to make good in an era of endemic police corruption and heightened racial tensions and in a city where everyone seems to be playing an angle.

While the template of a bruised hero in a nefarious world will strike fans of GTA and Red Dead Redemption as familiar, the gameplay for L.A. Noire may throw them one or two curveballs.

Here, players will not only become drawn in by the game's sympathetic protagonist, but their success in the game will depend largely on their ability to work out the motivations of many of the characters in his environment. While the action is punctuated by the odd fist-fight, car chase or shoot-out, L.A. Noire is an altogether more cerebral affair, which involves the player engaging in a lot of police-work. They'll need to collect clues, work crime-scenes, piece together evidence and interrogate suspects.

This last aspect can't be overstated in either its importance or the impressive way in which its been presented in the game. Using a groundbreaking 3D motion-capture technology called Depth Analysis, the developers have made the aspect of talking to witnesses feel incredibly lifelike. The level of detail the technology is capable of reproducing on screen is such that it necessitated the casting of Hollywood actors – including Mad Men's Aaron Staton, who plays the game's hero, Phelps.. You almost do a double-take when you see the tech in action; every wrinkle, every facial tick and every eye-movement of each character's face is faithfully recreated in the game. Each interrogation makes the player feel like they're engaging with a living, breathing human being, and they'll need to watch for body language and facial tells to see whether or not they're being deceived in their enquiries.

As the game progresses, Phelps makes his way up from beat cop and through the LAPD's different divisions such as Homicide, Vice and Robbery. Each 'desk has around seven or eight cases to solve but they're all tied together by Phelps's hunt for a serial killer at large in the City Of Angels. Each crime Phelps investigates starts with a visit to a crime scene – like a dark alley where a perp is suspected of ditching their firearm or a sun-kissed back-lot where the body of a brutally murdered woman lies motionless in the grass. As the player guides Phelps around each crime scene, they'll be on the lookout for clues such as drag-marks, blood-stains and the odd item which can be picked up and examined more closely. A sinister piano bar tinkles out when they approach an area containing something of interest. Not all clues are necessarily useful, however, and L.A. Noire, we're told, contains quite a few red herrings. As Phelps gathers clues and picks through crime scenes, his notebook begins to fill up with evidence, which provides the player with more ammunition to use on suspects in interrogation scenes.

The game doesn't skimp on brutality and some of the crime-scenes Phelps encounters are graphic to say the least. One case called “The Red Lipstick Murder”, features the naked corpse of a woman laid out on the ground, with words scrawled across her stomach. In close proximity, Phelps sees that part of her skull is missing, and when he moves her head to survey the damage, her neck makes a sickening, crackling sound. Scenes such as this mark L.A. Noire out as adults-only entertainment, but it has to be said, that there's nothing gratuitous about the game. Many of the cases, we're told, were inspired by real-life headlines from LA newspapers in the 1940s, and it should also be pointed out that all of the violence is handled responsibly and at the service of the plot.

The best thing about L.A. Noire is how the technology, the story and the interesting game mechanics blend seamlessly together immersing the player in the shadowy atmosphere of a noir thriller. In the short amount of time we had with it, L.A. Noire impressed us with its boldness and creativity. Few games have managed to make characters so believable, or captured the ambiance of the grimy and glitzy period setting. The game's city of Los Angeles feels filled to bursting with dark promise; around every corner there's a new crime to solve, a new criminal to bring down, and a new victim who cries out for justice. If L.A. Noire lives up the promise of what we've been shown so far, it could be one of this year's best games. Chandler and Hammett would be proud...